Silicon carbide (SiC) is a chemically stable ceramic material that is widely used in applications requiring high mechanical endurance and high thermal stability.
The SiC has various crystal structures such as cubic, hexagonal, and rhombohedral systems, among which, extensive studies on the cubic SiC have been conducted because the cubic SiC can be prepared easily and economically. In particular, the one-dimensional (1D) cubic SiC is useful for preparing a diesel particulate filter or a ceramic fiber filter having high tensile strength because the 1D cubic SiC has a large specific surface area and high surface-to-volume ratio with a porous structure.
Various methods for preparing the 1D cubic SiC structure have been developed. Examples for the method include chemical vapor deposition (G. Y. Li et. al., J. Phys. Chem. C, 2009, 113, 17655), carbothermal reduction (B-H. Yoon et. al., J. Am. Ceram. Soc., 2007, 90, 3759), and template synthesis (H. Cui et. al., Chem. Comm., 2009, 6243). However, these methods have many difficult problems, e.g., low reproducibility and difficulty in application for a large scale processing. Further, the template synthesis method is complicated because a subsequent chemical process for removing the template must be conducted.
Recently, there has been introduced a method for preparing SiC fibers which comprises the step of electrospinning an SiC precursor, a commercially available polycarbosilane so as to resolve the above-mentioned problems and to obtain a micro-scale SiC fiber in large quantities. However, this method has a difficulty in preparing a nano-scale SiC fiber in a high purity because the polycarbosilane must be used in a high concentration of 50% by weight or more due to its low molecular weight.
Accordingly, there has been a need for developing a novel method for preparing a single crystalline SiC nanofiber having excellent thermal and mechanical stability with a large specific surface area.